Father Lyonnet, expert in Catholic exegesis, delves into themes in this work whose actuality and transcendence cannot be denied: the Eucharist is the life-source of the cult wanted by God and ratified by the Church in the unconditional adherence to the brother who requires a life of dignity, only possible through justice and charity. The celebration of the Eucharist does not only require that the participants feel united during the liturgy; it requires a much more profound transformation: for the rest of life.